The present invention relates generally to the field of floor covering underlayments and floor covering systems that include floor covering underlayments. In particular, the invention is directed to a floor covering underlayment that comprises a polyurethane foam material, and floor systems that include such an underlayment.
It has long been common practice in the flooring industry to use underlayment materials between a subfloor and a non-textile floor covering installed onto the subfloor. Such non-textile floor coverings include, for instance, vinyl tile floors, sheet vinyl floors, linoleum floors, hardwood floors and various other types of laminated floors.
The underlayment material can serve one or more of a variety of different functions in a given installation. In some installations, the function of the underlayment material is to provide a cushioning effect to the floor system. In other situations, the function of the underlayment material is to compensate for imperfections in the surface of the subfloor, which can be concrete, plywood, or a number of other different materials that are commonly used and known. Another function of the underlayment, which is particularly pertinent to the present invention, is to reduce the transmission of sound through the floor to a room below in a multi-floor building. This is particularly significant where the maximum allowable level of sound transmission is controlled by local building codes, which is increasingly common.
A variety of different underlayment materials have been developed in the past. Perhaps the most widely used underlayment material has been a simple polyethylene foam material. Other products have been made in which a polyethylene foam is coated on one side with a polyethylene film as a moisture barrier. Other products have been made using polystyrene foams, some of which have included foil or mylar coatings on one side of the material. Products have also been made using re-ground rubber buffings adhered to a substrate. One such product has been marketed under the trademark DURASON by Durie of Montreal, Canada. Other products have been made using slab rubber, for example, a product marketed under the trademark TREAD-AIRE, by Gates Rubber, located in the United Kingdom. The TREAD-AIRE product comprises a rubber sheet, with a substrate material on one side. Underlayment products have also been manufactured from compressed cellulose.
While all of the aforementioned products have proven useful in various circumstances, they all have substantial disadvantages or drawbacks. For example, while polyethylene foam underlayment materials are effective in smoothing imperfections on the subfloor surface, such products are relatively ineffective in reducing the transmission of sound through the floor to a room below in a multi-story building. The same is true for the various coated polyethylene and polystyrene foam products that have been developed. While slab rubber and compressed cellulose products are effective to some extent in reducing the transmission of sound through the floor to a room below, they are relatively difficult to handle and install. For instance, products made from slab rubber tend to be quite heavy as compared to the lighter foam products, and are therefore more difficult to carry and install. Compressed cellulose products are generally provided in the form of rigid square tiles. As a result, the installation of such products is more difficult than other products that can simply be rolled into place. In addition, the slab rubber and compressed cellulose products tend to be quite thick, on the order of 0.180 inches or greater. In situations where a new floor is to be installed into a pre-existing building, the use of such a thick underlayment can raise the level of the floor to an extent that makes it necessary to remove and reposition the existing baseboards and moldings around the floor.
In view of these shortcomings in the existing underlayment products, there is a need in the industry for an improved underlayment material that is relatively thin and easy to install, that can be provided to end users in the form of a roll, that is capable of smoothing imperfections in the subfloor, that is capable of providing a cushioning effect for the floor structure, and that is capable of substantially reducing the transmission of sound through the floor to a room below in a multi-story structure. These and a number of additional objectives are met by the present invention.
In a basic aspect, the present invention is a polyurethane foam underlayment material for use with non-textile floors, and includes flooring systems that incorporate such underlayment materials. In one embodiment, the foam is a mechanically frothed polyurethane foam. In a particularly preferred embodiment, a fabric layer, such as a layer of non-woven spun bonded polyester fibers, is bonded as a substrate to one of the primary surfaces of the polyurethane foam.
The underlayment material is provided in the form of a thin, flexible sheet, which can be provided to an end user in the form of a roll and unrolled easily over the subfloor. Thus, it is at least as easy to install as any existing products. It is also relatively lightweight, reducing shipping costs and making the product easier to handle as compared to some other types of products. The underlayment is effective at smoothing imperfections in the subfloor and providing a cushioning effect for the floor structure. Surprisingly, while the product is much thinner than most underlayment products, it is excellent at reducing sound transmission through the floor to a room below in a multi-story structure.